1. Field of the Invention
The present invention relates to a device and method or aiding the positioning of an external part relative to an implantable part of a charging system for charging a rechargeable power source of an implantable medical device. In particular the present invention relates to such devices and method where an external transmitting part and an internal receiving part are provided with a resonant circuits with coils which can be inductively coupled to one another for transcutaneous power transmission by manual positioning of the external transmitting part.
2. Description of Related Art
A device and a process of this general type are known from U.S. Pat. No. 5,279,292. In this reference, a telemetry circuit is assigned to the charging electronics of a receiving part which delivers a signal to the outside which is characterized by the mutual alignment of the transmitting and receiving part (such as those discussed in Leysieffer et al. "A completely implantable hearing system for the hearing impaired: TICA LZ3001" in HNO. 46:853-863 (1998)), thereby providing to the implant wearer information relating to the positioning of the transmitting part relative to the receiving part during the charging process through acoustic signals which are supplied to the acoustic signal path of a hearing aid. In another known device for aiding the positioning of a charging system for implantable medical device as shown in U.S. Pat. No. 5,690,693, the correct mutual alignment of the transmitting part and receiving part is optically displayed on the transmitting part based on the current flowing through the transmitting coil.